The present invention relates to a plug made of plastic and which is utilized for anchoring objects flush or in spaced relationship in a support structure, for example of concrete.
Plastic plugs of the type under consideration have an elongated bore which receives a fastening screw, an expansible portion which is anchored in a concrete structure, by screwing in of that fastening screw, and an elongated neck which can have ribs to secure the anchored plug against rotation.
Plugs having elongated necks are normally used for securing objects such as frames and battens to a support structure wherein the elongated neck engages the object to be secured. The function of the elongated neck is to guide the fastening screw in the plug and to fill the annular gap between the shaft of the fastening screw and the wall of the drilled hole in the object to be secured. In addition, the elongated neck may serve as a bridge for void places and in flush mountings to ensure sufficient anchoring depths, especially in porous building materials such as foam concrete and the like.
Greater anchoring depths can lead to an increase in pull-out force values if the cause of failure is that the anchoring base breaks away.
Anchoring plugs of the foregoing type have been disclosed in numerous U.S. patents of the inventor, for example U.S. Pat. Nos. 4,094,054; 4,149,350, etc.